The transesterification reaction between polyols and alkyl acetoacetates is known. See, e.g., U.S. Pat. Nos. 3,892,903, 3,691,112, and 3,666,726. In addition, the reaction of acetoacetic acid esters with isocyanates is also known. See, e.g., U.S. Pat. Nos. 3,892,903, 2,801,990, 4,068,086, 4,132,843, and 4,332,965. In the last four mentioned U.S. patents, blocked isocyanates are prepared via such reaction In the '903 patent, the transesterified products are reacted with crosslinking agents to produce high solids coating compositions. Diisocyanates can be included with the crosslinking agents described.
U.S. Pat. No. 4,218,543 describes the production of reaction injection molded (RIM) products using reaction mixtures of diisocyanates or polyisocyanates based on 4,4'-diisocyanatodiphenyl methane, aromatic polyamines, and relatively high molecular weight polyhydroxyl compounds.
Recent advances in the RIM area have been directed to the substitution of so-called "amino-polyethers" for all or a portion of the relatively high molecular weight polyhydroxyl compounds. See, e.g. U.S. Pat. Nos. 4,774,263, 4,396,729, 4,433,067, 4,444,910, 4,530,941 and 4,590,219; and German Offenlegungsschriften 3,215,907 and 3,215,909. Typically, the isocyanates used with the amino-polyethers have included (i) liquid products made by reacting 4,4'-diphenylmethane diisocyanate with tripropylene glycol, (ii) liquid modified 4,4'-diphenylmethane diisocyanates containing carbodiimide groups and (iii) prepolymers from 4,4'-diphenylmethane diisocyanate and polyethers (see the first five references noted in this paragraph). U.S. Pat. No. 4,590,219 also describes the use of a prepolymer from 4,4'-diphenylmethane diisocyanate and a diethylene glycol adipate (having an OH number of 42).
Recently, our company has evaluated the use of a prepolymer derived from 4,4'-diphenylmethane diisocyanate, a polyester (having a molecular weight of 2000 and produced from adipic acid, ethylene glycol, and butanediol), and a carbodiimidized 4,4'-diphenylmethane diisocyanate
Finally, U.S. Pat. No. 4,857,561 describes prepolymers derived from MDI and neopentyl adipate polyesters and the use thereof in a RIM process.